This kind of film forming unit for a sputtering apparatus is known, e.g., in Patent Document 1. The unit in question is provided with a box-shaped enclosure (displacement part) which is mounted on an inner wall surface of a vacuum chamber in which film forming is performed, and a displacement plate is disposed on that side surface of the enclosure which looks inward of the vacuum chamber. The displacement plate has fixed thereto, through a supporting body, a backing plate which has a target bonded to one surface as a cathode. Further, positioned on the inside of an opening which is provided in the displacement plate, a magnet unit for causing to function a leakage magnetic field on the surface of the target is fixed to the inside of the supporting body.
The inside of the enclosure is divided by a partition wall into two chambers. One of the chambers is in communication, through a penetrating hole opened in the enclosure, with a space on the side of the target, i.e., with the vacuum chamber which is evacuated for performing film forming processing therein. The other chamber is provided with a driving motor, and a driving shaft of the driving motor penetrates the partition wall to protrude into said one chamber. At a tip of this protruded driving shaft, there is provided a connection rod, and the connection rod is connected to a displacement plate. In this arrangement, when the driving motor is driven, the backing plate which is fixed to the displacement plate through a supporting plate and, consequently, the target makes a relative movement in relation to the magnet unit. According to this arrangement, when a rare gas or a reactive gas for electric discharging at the time of reactive sputtering is introduced into the vacuum chamber and, while the target is sputtered by applying predetermined electric power, e.g., with negative potential, the relative positions of the magnet unit do not change, even if the target is moved, and of a deposition-preventive plate (anode) to be provided in front of the target which looks inward of the vacuum chamber, do not change. Changes in the conditions of the plasma such as the position, density and the like of plasma on the surface of the target can thus be restrained.
In the above-mentioned prior art, however, since the enclosure of the film forming unit is directly mounted on the inner wall surface of the vacuum chamber, there are problems in that the mounting and dismounting of the film forming unit are troublesome, resulting in inconvenience in maintenance. Further, during sputtering, it is necessary to supply the backing plate with cooling medium such as cooling water. For that purpose, it is necessary to separately provide the wall surface of the vacuum chamber with water supply pipes and water distributing pipes separately, thereby resulting in complex apparatus arrangement.